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dt23
03-04-2004, 01:30 AM
Hi,

I just installed a Linux Mandrake 9.2 system. I can access the Internet with it no problem. However, when I try to ping the new system from another pc on the network, I get no response.

I thought it might be a firewall issue, but I have the Linux machine set to not use a firewall... I also do not get a response when I ping 127.0.0.1 on it.

Might anyone be able to tell me how I can go about getting access to the new machine from the outside?
cowanrl
03-04-2004, 08:01 AM
Execute this command:

cat /proc/sys/net/ipv4/icmp_echo_ignore_all

If it returns a 1, then your machine is set up to ignore ping requests. In that case execute as root:

echo 0 > /proc/sys/net/ipv4/icmp_echo_ignore_all

to allow your machine to respond to ping requests.
deathadder
03-04-2004, 09:12 AM
How does it get a IP address, DHCP? Have you tried the machines name as well as the IP address:

ping -c 3 darkstar
or
ping -c 3 192.168.0.2
dt23
03-04-2004, 05:56 PM
That did the trick! Thanks... my machine wasn't set up to accept pings it seems.

(Yes, it's DHCP and I did try pinging the machine name as well)

Thanks again.

-dt23
dt23
03-05-2004, 10:54 PM
Hey, is there a way to set that I don't have to type:
echo 0 > /proc/sys/net/ipv4/icmp_echo_ignore_all
each time I reboot the machine?

TIA,
dt23
bwkaz
03-06-2004, 12:37 AM
Put that command into a boot script (if you have an /etc/rc.d/init.d/rc.local, put it at the beginning of that file).
nouse66
03-06-2004, 12:51 AM
is there any reason mandrake would come default that way?
dt23
03-06-2004, 01:04 AM
Found it. Works great, thanks.

-dt23
cowanrl
03-06-2004, 07:49 AM
Originally posted by nouse66
is there any reason mandrake would come default that way?

It would be a security issue. If your computer does not respond to pings, it makes it a little bit harder to find on a network. It would not show up in a casual ping scan of the network. A ping scan is one of the first and easiest methods used to find out what machines are up on a network. Once it's detected with a ping, a hacker could then use a port scanner to check the computer for vulnerabilities.

It doesn't make the computer invisible, it just takes a little more effort to detect it.